L-type Ca2+ channel blockers in HTN

Question 1

There are three classes of L-type Ca2+ channel blockers mentioned with one drug mentioned in each class. Name them

Answer 1

1. Phenylalkylamines- Verapamil
2. Benzothiazapines- Deltiazem
3. Dihydropyridines- Nifedipine (they all end in “pine”)

Question 2

What differentiates verapamil from the others?

Answer 2

selective for myocardium

Question 3

what differentiates deltiazem from the others?

Answer 3

intermediate in selectivity between cardiac/vascular Ca2+ channels

Question 4

What differentiates the dihydropyridines (nifedipine) from the others?

Answer 4

selective for vessels.. treats HTN

Question 5

So, the dihydropyridines are the Ca2+ channels blockers of choice for lowering BP. How do they do this?

Answer 5

They decrease intracellular Ca2+ of smooth muscle which leads to vasodilation and decreased BP

Question 6

Are the dihydropyridines good for pts with low or high renin HTN?

Answer 6

Low renin HTN

Question 7

4 side effects of the dihydropyridines

Answer 7

1. Hypotension
2. Reflex tachycardia
3. Ankle edema
4. Constipation